Surgical spacer placement using an expanded polytetrafluoroethylene sheet in proton beam therapy for pediatric solid tumors

Abstract

Proton beam therapy for pediatric malignant solid tumors has recently been covered by the national health insurance in Japan, and opportunities for surgical spacer placement have increased, facilitating more effective radiotherapy. We performed spacer placement using an expanded polytetrafluoroethylene (ePTFE) sheet as a spacer material for four children with malignant pelvic tumors. The tumor surface was covered with five 2-mm-thick patches to secure a 10-mm margin, which reduced the exposure of the intestine and prevented dose reduction at the tumor edge. In all these patients, no postoperative complications were observed, and proton beam irradiation was performed as planned. Since the safety of the ePTFE sheet remaining in the body has not been established, we removed the spacer after irradiation in three of these patients. Recently, a bio-absorbable spacer has been developed; thus, ePTFE sheets are expected to fall out of use as spacers in the future. However, it is possible to apply spacer placement techniques to absorbent spacers as well. We herein summarize and report our experiences in treating these four patients.